Steam-actuated  valve



(No Model.)

E. M. PIERCE.

STEAM AGTUATED VALVE. V No. 340,729. Patented Apr. Z7, 1886.

WM/WM PETERS, Phmumagnmr. vla-mum". n. cg

UNITED STATES PATENT OFFICE.

FRANCIS M. PIERCE, OF BROOKLYN, NEV YORK.

S'l'EAM-ACTUATED VALVE.

SPECIFICATION forming part of Letters Patent No. 340,729, dated April 2'7, 1886.

.Application filed January r2, 1386.

To all whom it may concern:

Be it known that I, FRANCIS M. PIERCE, a citizen of the United States, residing at Brooklyn, in the county of Kings, State of New York, have invented certain new and useful Improvements in Steam-Actuated Valves, of which the following is a description.

My invention relates to improved means for operating steam-actuated valves, the details whereoi` will be hereinafter fully set forth.

In the accompanying drawings, Figure l is a longitudinal sectional elevation of the cylinder, steam chest, and piston of a rockdrilling engine, non-essential details being omitted. Fig. 2 is a sectional plan view through the center of the steanrchest on the lines 2 2 of Fig. l, part of the iiange of the valve being broken away to more clearly show the steam-ports. Fig. 3 is a view similar to Fig. 2, thc. valve and detachable portions being removed to more clearly show the pas sages extending therethrough.l Fig. 4 is a View of the port-face ot' the cylinder, a portion thereof being broken away to show the nature and direction of the passages. Fig. 5 is an inverted plan View of the steam-chest. Fig` 6 is a central vertical section on the line 6 (5 of Fig. l. Fig. 7 is a vertical section on the line 7 7 of all the views except Fig. 6.

Similar letters denote like parts.

A represents the cylinder of a rock-.drilling engine,which may be operated by compressed air, steam, or other duid.

The invention is applicable to other engines, but is here shown and will be described as applied to steam (or air) rock-drills, it requiring no invention to apply it to other engines to which it is suited.

The cylinder is formed with the usual steam and exhaust ports and passages, lettered, respectively, a a.

B is the piston, and b the piston-rod. C is the steam-chest, within which reciprocates a cylindrical valve, D, by means of which the admission to 'and exhaust from the alternate ends of the cylinder are controlled in the wellknown manner. Steam entering at E passes through the valve and steam-passages to the cylinder, the exhaust-steam escaping through the passage a and exi-t E.

|The valve D is spool-shaped, and its ends d are provided with packing-rings, which t the bore of the steamchest. This valve has a hole through its longitudinal axis,through which passes the bolt F, which is fixed in the steam-chest C,aud serves to guide the valve in its reciprocations, and by means of a spline prevents its rolling on its seat. The bolt F is formed with short narrow slots f f', extending inward from each end toward the interior of the steam-chest, and the valve D is formed with small steamvports e c, leading from its upper side through its longitudinal portion,

and adapted to communicate at predetermined periods with the slots in its support F, forming alternating connections between the livesteam supply and the ends of the steam-chest,

and by means of which the valve is driven positively buck and forth upon its seat in accordance with the movements of the rest of 7c the apparatus.

In the bottom of' the steam chest are two cored passages, G H, connecting opposite ends of the steamchest with the short tubes or passages I K, which lead from the portface of 75 the cylinder through to its interior. The passages G I-I pass upward in the walls of the steam-chest and then traverse it in opposite directions, opening upward in the form of narrow ports g lr at opposite ends ofthe steamchest, so that one end of the steam-chest is at all times in direct connection with the interior exhaust-chamber of the main cylinder.

The piston B is of ordinary construction, and of a length sufficient to` cover and close the lower tube, I, when in its extreme upper position, and it is formed with an annular recess, L, at'its central portion, which recess should be shorter 4than the distance between the tubes I K. A pair of openings, ik, located in the side of the cylinder A and in the same plane as the tubes I K, respectively, pass through the sides of the cylinder and into the exhaust-passage a', and whenever the recess L of the piston covers either of the tubes I K it also covers the corresponding exhaust-passage, from which it will be understood that in the ordinary working of the engine one or other of the valve-controlling ports will be closed by the body of the piston, while the other, being covered by the recessed portion thereof, will have free access to the atmosphere.

The operation of the device will loe explained with the parts in the positions shown,

ICO

e eficaz@ the space between the valve and end of the steanrchest being designated by the letter M. Assuming the engine to have made a number of strokes and to be in position to begin the power-stroke, the conditions are as follows: Piston raised; valve lowered; upper steampassage ready to receive live steam; space M above the valve iilled with the steam that forced it down, which is confined therein by the closure of the port e and tube I, resulting from the relative positions of the valve and piston. These conditions prevail until the piston descends far enough for the recess L to 'establish communication between the tube I Yand its exhaust, when the steam in the space .Mis released, and the tube K, representing the opposite end of the steam-chest, closed. The steam, passing through the port e and passage f, and having no outlet, now accumulates between the end of the steam-chest and the valve and balances that end of the valve, while the unbalanced pressure at the other end drives it to the opposite extremity of the steam-chest. 'Ihe ports e e are short, as also are the passages ff', so that before the valve has completed its movement the im-v pelling Huid is cut ott, the valve being moved through the remainder of its traverse by the expansion of the now imprisoned force, which holds it in position, notwithstanding the fact that the opposing set of passages are in position to receive live steam, because until the steam confined as just described is liberated the live steam entering the opposite passages is powerless to move the valve, and escapes through its exhaust.

The amount of steam used to throw the valve can be regulated according to the demands of practice by proper adjustment of the size of the ports e c and the size and length of the slotsff; and, further, the rapidity and force of its throw can be regulated by the size of the passages G H and tubes I K, the tube I being, as herein shown, reduced in area, so that the exhaust from the upper end of the steam-chest may be somwhat checked, the intention being to practically cushion the valve on its upward throw.

I do not confine myself to the exact details of the construction and arrangement herein shown, as many modications may be made by those skilled in the art without departing from the spirit of the invention.

Having described my invention, what I claim, and desire to secure by Letters Patent, 1s-

1. The combination, with the steam-cylinder and steam-chest, of a reciprocating valve controlling the steam and exhaust passages to the cylinder, supplemental steam and exhaust passages for positively actuating the Valve, the supplemental steampassages being controlled by the valve, and means carried by the piston ofthe engine for alternately opening and closing the valve controlling passages, as described.

2. The combination, with the cylinder of a drilling engine, of a reciprocating spool shaped valve, a longitudinal fixed support for said valve, steam ports and passages extending from the longitudinal portion of said valve along its support and to the ends of the steamchest, supplementary exhaust-passages leading from the ends of the steamchest to the main exhaust, a piston formed with a recess therein and adapted to alternately open and close the valve-operating passages, as described.

8. The combination, with the drilling-engine having a suitable steam-chest, of the spool-shaped valve D, having steam-ports e e', a longitudinal fixed support therefor provided with the steam-passages ff, the exhaust-passages G I-I, tubes I K, passages i k, and the piston provided with recess L, substantially as shown and described.

In testimony whereof I hereto affix my signature in presenceof two witnesses.

FRANCIS M. PIERCE. Vitnesses:

JOHN CUYAT, WM. L. SAUNDERs. 

